The present invention relates to a new and improved construction of a guide vane support or carrier for a gas turbine, the guide vane support being constructed as a two-part or bipartite structure and is equipped with cooling channels. The guide vane or blade support carries cooled guide vanes or blades and concentrically to the lengthwise axis of the turbine possesses a substantially conical construction.
In machines which are operated by a working medium at high pressure and high temperature, for instance gas turbines, the problems which arise most frequently occur at those components or parts which are directly subjected to the action of the hot process or working gases. These problems are essentially attributable to the reduced strength of the materials from which these components are formed, when exposed to the high operating temperatures, and to the increased corrosion proneness of such components or parts. Moreover, high static and non-static thermal stresses arise at such components, so that the sealing of unavoidable expansion gaps becomes difficult which, depending upon the operating state of the equipment can vary, i.e. between start-up and shutdown of the gas turbine, and render problematic a leakage-free infeed and withdrawal of the cooling agent or medium.
The guide vane supports or carriers of gas turbines take-up the aerodynamic forces which act upon the guide vanes or blades and transmit such to the housing or casing, wherein, however, the guide vane supports, at relatively higher inherent temperature, are not subjected to the typical boiler stresses like the machine housing. Furthermore, such type guide vane supports are constructed as separate components or parts, thus affording the possibility that they can freely expand by virtue of their inherent temperature. These guide vane supports are arranged in conventional manner within the machine housing such that they advantageously are fixed and sealed at the flow downstream located cooler components or parts.
The continuous increase in the output and efficiency of gas turbines is obtained by increasing the operating temperatures and operating pressures. Consequently, cooling becomes increasingly more problematic because owing to the high compressor-final or exit pressure and the high compressor exit temperature of the compressed air the air temperature is much too high for use for cooling the endangered components or parts and no longer can be effectively employed as a cooling agent or medium.